Annual report pursuant to Section 13 and 15(d)

Short-Term And Long-Term Investments And Restricted Deposits (Contractual Maturities Of Short-Term And Long-Term Investments And Restricted Deposits) (Details)

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Short-Term And Long-Term Investments And Restricted Deposits (Contractual Maturities Of Short-Term And Long-Term Investments And Restricted Deposits) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Investments [Member]
    
Schedule of Available-for-sale Securities [Line Items]    
One year or less, Amortized Cost $ 138,011 $ 129,232
One year through five years, Amortized Cost 474,068 406,140
Five years through ten years, Amortized Cost 94,006 34,945
Greater than ten years, Amortized Cost 38,799 56,720
Total, Amortized Cost 744,884 627,037
One year or less, Fair Value 139,118 130,499
One year through five years, Fair Value 481,381 413,953
Five years through ten years, Fair Value 93,878 34,961
Greater than ten years, Fair Value 39,464 57,226
Total, Fair Value 753,841 636,639
Restricted Deposits [Member]
    
Schedule of Available-for-sale Securities [Line Items]    
One year or less, Amortized Cost 34,403 19,666
One year through five years, Amortized Cost 358 7,085
Five years through ten years, Amortized Cost 0 0
Greater than ten years, Amortized Cost 0 0
Total, Amortized Cost 34,761 26,751
One year or less, Fair Value 34,435 19,666
One year through five years, Fair Value 358 7,152
Five years through ten years, Fair Value 0 0
Greater than ten years, Fair Value 0 0
Total, Fair Value $ 34,793 $ 26,818